Forces and motion are a part of your everyday life for
example pushing a trolley, a horse pulling a rope, speed
and acceleration. Force and motion causes objects to
move but also to stay still. Motion is simply a movement
but needs a force to move. There are 2 types of forces,
contact forces and act at a distance force.
Forces
Every day you are using forces. Force is basically push
and pull. When you push and pull you are applying a
force to an object. If you are Appling force to an object
you are changing the objects motion. For an example
when a ball is coming your way and then you push it
away. The motion of the ball is changed because you
applied a force.
Different Types of Forces
There are more forces than push or pull. Scientists group
all these forces into two groups. The first group is contact
forces, contact forces are forces when 2 objects are
physically interacting with each other by touching. The
second group is act at a distance force, act at a distance
force is when 2 objects that are interacting with each
other but not physically touching.
Contact Forces
There are different types of contact forces like normal
Force, spring force, applied force and tension force.
Normal force is when nothing is happening like a book
lying on a table because gravity is pulling it down.
Another contact force is spring force, spring force is
created by a compressed or stretched spring that could
push or pull.
Applied force is when someone is applying a force to an
object, for example a horse pulling a rope or a boy
throwing a snow ball.
Tension force is a force that is applied to a cable or a
wire. Tension force causes a force to pull equally in each
direction.
Friction
Friction is another contact force. It can be helpful and
it allows you to let you walk without sliding. The heavier
an object is the more friction it has. Friction can be
destructive for example if you rub out the mistakes you
made, the rubber become smaller and smaller.
There are 4 types of friction sliding friction, static
friction, rolling friction and fluid friction.
Sliding friction is produced when the bumps on the
surface stick together, sliding friction can also slow
down objects. Sliding friction occurs when two objects
slide past each other.
Static friction is the friction that acts upon unmoving
objects. If a force is greater than static friction, static
friction is no longer applied.
Rolling friction is a frictional force between a rolling
object and the surface. Rolling friction is much less than
sliding friction, but it depends on the surface, for
example cars wheels and shopping trolley wheels.
Fluid fiction is a friction that resists motion when fluid
is involved, like water going through a hose.
Air resistance is friction, it can slow things down or
speed things up for example wind blowing a leaf.
Inertia
Inertia is not a force it is a property of all things due to
their weight and their mass. Inertia makes objects move
easier or harder, it depends on their mass. The more
mass the object has the more inertia it has.
Non-Contact Forces
Magnetism is a Non- contact force,
magnetism is invisible to the human eye
and it can be made with useful tools and
machines. In the 1700s scientists discovered that
magnetism has similar features as electricity.
Magnetism is not attracted to silver, gold, platinum and
aluminium.
Gravity is another non-contact force. Gravity is the force
that pulls you down and allows you to stay on earth
instead of floating off. Gravity means what comes up
must come down. Gravity is keeping us in orbit, because
the suns gravitational pull keeps our planet in orbit. The
moon is affected by the suns gravity and the earths’
gravity. The moons gravity is the reason why our tides go
up and down. Weight effects gravity for example if you
drop an acorn it will fall slower than a piano because
the piano is heavier than the acorn. Sir Isaac newton
was the person that discovered gravity but he didn’t
know how to explain it. Then Albert Einstein came along
and explained how gravity works.
Motion
Motion makes objects speed up or slow down. Motion
makes things move or go round.
Velocity is the speed of an object in one direction, if the
direction changes speed and velocity changes.
Acceleration is how quickly objects speed up.
Important people
Sir Isaac newton is the greatest English mathmatition.
He made the 3 laws of motion, his first law was if
something is moving and it keeps on moving or at rest it
will stay still (INERTIA). His second law is if a force is
acting on an object, it will change its speed and his
third law was for every force or action there is an equal
or opposite reaction. Albert Einstein was a scientist; he is
also the most famous person of all time. Albert Einstein
refined some of newtons theories through his own
theories of relativity.
If you push or pull you are changing the objects motion.
A force must be Appling on an object to set it in motion.
Forces and motion are always going to be part of your
life no matter what!!
Written and published by: Manu
This is Albert Einstein and Sir Isaac
Newton. Below them are there
Theories.
Albert Einstein
is the person
who defined
gravity.